Abstract : This paper analyzes several theories of multi-agent collaboration. We have chosen three to study more closely than the others. While these contain what we believe to be the essential elements of a multi-agent collaboration, each approaches this idea somewhat differently. This is followed by a less-extensive review of several other theories, a number of which allow for contractual relationships. This analysis reveals not only relative strengths and weaknesses between the theories, but also illustrates the differences when agents collaborate and when they have a contractual association, the line between which is often blurred in the literature. Finally, we present two real-world domains, and discuss the advantages and disadvantages of these theories to each domain.